JP2023529881A - Lithium-ion cells with specific high energy density - Google Patents

Abstract

A known lithium-ion cell (100) includes an electrode-separator assembly (104) having a sequence of anode (120)/separator (118)/cathode (130), wherein the anode (120) and cathode (130) are each: current collectors (110, 115) having first and second edges (110e, 115e), each of these current collectors having a main region provided with a layer of respective electrode material (123, 125); (122, 126) and free edge strips (121, 117) extending along first edges (110e, 115e) not equipped with electrode material. The assembly (104) is in the form of a roll with two end faces or is part of a stack formed from two or more identical electrode-separator assemblies that also have two end faces. , optionally together with one or more additional identical electrode-separator assemblies of the stack, enclosed in a housing. The anode (120) and cathode (130) are arranged such that the first edge (110e) of the anode current collector protrudes from one of the end faces or pages of the stack, and the first edge (115e) of the cathode current collector. are formed and/or positioned relative to each other within the assembly (104) such that they protrude from the end face of the stack or the other of the pages. The cell (100) has a contact plate metal member (101a, 102, 155) with one of the first edges (110e, 115e) in direct contact with the contact plate metal member (101a, 102, 155). A sheet metal member is connected to the first edge by welding. The negative electrode material is selected as active material from the group consisting of silicon, aluminum, tin, antimony, and compounds or alloys of these materials that are capable of reversibly intercalating and deintercalating lithium. It is proposed to contain at least one material from 20 wt% to 90 wt%.

Description

The invention described below relates to lithium ion cells with electrode-separator assemblies.

Electrochemical cells can convert stored chemical energy into electrical energy through redox reactions. An electrochemical cell generally comprises a positive electrode and a negative electrode separated by a separator. During discharge, electrons are released at the negative electrode as a result of the oxidation process. This results in an electronic current that can be drawn by an external electrical consumer, for which the electrochemical cell acts as an energy supplier. At the same time, an ionic current corresponding to the electrode reaction is generated inside the cell. This ionic current traverses the separator and is ensured by the ion-conducting electrolyte.

If the discharge is reversible, ie the conversion of chemical energy to electrical energy that takes place during discharge can be reversed and the cell can therefore be charged again, it is called a secondary cell. As commonly used in secondary cells, referring to the negative electrode as the anode and the positive electrode as the cathode refers to the discharge function of the electrochemical cell.

Widely used secondary lithium ion cells are based on the use of lithium, which in ionic form can be transferred between the electrodes of the cell. Lithium-ion cells are characterized by relatively high energy densities. The negative and positive electrodes of lithium-ion cells are generally formed by so-called composite electrodes, which contain electrochemically active and electrochemically inactive components.

In principle, all materials capable of absorbing and releasing lithium ions can be used as electrochemically active constituents (active materials) of secondary lithium ion cells. Carbon-based particles, such as graphitic carbon, are often used in negative electrodes. Other non-graphitic carbon materials suitable for lithium intercalation can also be used. In addition, metallic and semi-metallic materials that can be alloyed with lithium can also be used. For example, the elements tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. For example, lithium cobalt oxide (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium titanate (Li ₄ Ti ₅ O ₁₂ ) or lithium iron phosphate (LiFePO ₄ ) or a derivative thereof may be used as the positive electrode active material. can be used as The electrochemically active substance is generally contained in the electrode in the form of particles.

As an electrochemically inert component, a composite electrode generally comprises a flat and/or strip-like current collector, such as a metal foil, coated with an active material. For example, the negative electrode current collector (anode current collector) may be made of copper or nickel, and the positive electrode current collector (cathode current collector) may be made of aluminum, for example. Additionally, the electrodes may include an electrode binder such as polyvinylidene fluoride (PVDF) or another polymer such as carboxymethylcellulose. This ensures the mechanical stability of the electrode and, more often, the adhesion of the active material to the current collector. In addition, the electrodes may contain conductivity-enhancing additives and other additives.

Lithium-ion cells typically contain as an electrolyte a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF ₆ ), in an organic solvent (eg, esters and ethers of carbonic acid).

During manufacture of a lithium ion cell, a composite electrode is combined with one or more separators to form an assembly. In most cases, the electrodes and separators are bonded together by lamination or gluing. The basic functionality of the cell can then be established by impregnating the composite with an electrolyte.

In many embodiments, the assemblies are formed flat such that multiple assemblies can be stacked flat on top of each other. However, often the assembly is manufactured as or processed into a roll.

Generally, the assembly, whether wound or not, includes a positive electrode/separator/negative electrode sequence. Often the assembly is manufactured as a so-called bicell with a feasible sequence: negative electrode/separator/positive electrode/separator/negative electrode or positive electrode/separator/negative electrode/separator/positive electrode.

For applications in the automotive field, e-bikes, or other applications with high energy requirements, such as in tools, lithium with the highest possible energy density that can be simultaneously loaded with high currents during charging and discharging I need an ion cell. Such cells are described, for example, in WO2017/215900A1.

Cells for the aforementioned applications are often designed as cylindrical round cells, for example having a form factor of 21×70 (diameter*height in mm). A cell of this kind always contains an assembly in the form of a roll. Modern lithium-ion cells with this form factor are already capable of achieving energy densities of up to 270 Wh/kg. However, this energy density is considered only an intermediate step. The market is already demanding cells with even higher energy densities.

However, there are other factors to consider in developing improved lithium-ion cells beyond just energy density. The internal resistance of the cell and the thermal connection of the electrodes are also very important parameters, the internal resistance of the cell should be kept as small as possible in order to reduce the power loss during charging and discharging, and the heat of the electrodes Connections may be essential for cell temperature regulation. These parameters are also very important for cylindrical round cells containing composite assemblies in the form of windings. During fast charging of a cell, heat accumulation may occur within the cell due to power loss, which may cause large thermo-mechanical stresses and subsequent deformation and damage of the cell structure. This danger is amplified when the electrical connections to the current collectors are made through separate conductor tabs welded to the current collectors that protrude axially from the wound assembly. Also, during charging and discharging, if a large load is applied, local heating may occur in these conductor tabs.

In particular, very high energy densities can be achieved when tin, aluminum, antimony, and/or silicon are used as negative electrode active materials. Silicon has a maximum capacity greater than 3500 mAh/g. This is about ten times the specific capacity of graphite. In practice, however, the use of electrode materials having a high proportion of the aforementioned metal active materials presents difficulties. Particles made of these materials undergo relatively large volume changes during charging and discharging. This results in mechanical stress and possibly mechanical damage. For example, proportions of silicon in the negative electrode greater than 10% have heretofore been difficult to control.

The object of the present invention is to provide a lithium ion cell characterized by an improved energy density compared to the prior art, while at the same time having excellent properties in terms of internal resistance and passive heat dissipation capability. Was that.

This object is achieved by the lithium-ion cell described below, in particular a preferred embodiment of the lithium-ion cell described below with the features of claim 1 . Preferred embodiments of this preferred embodiment also emerge from the dependent claims.
A lithium-ion cell according to the invention is always characterized by the following features a to j:
a. The cell comprises an electrode-separator assembly having an anode/separator/cathode sequence, preferably a ribbon electrode-separator assembly having an anode/separator/cathode sequence.
b. The anode comprises an anode current collector having first and second edges, preferably a ribbon-like anode current collector having first and second longitudinal edges and two ends.
c. The anode current collector is
- a main region provided with a layer of negative electrode material, preferably a strip-like main region provided with a layer of negative electrode material;
- a free edge strip extending along a first edge of the anode current collector, in particular along a first longitudinal edge of the anode current collector, the free edge strip not being provided with electrode material; have
d. The cathode includes a cathode current collector having first and second edges, preferably a ribbon-like cathode current collector having first and second longitudinal edges and two ends.
e. The cathode current collector is
- a main region provided with a layer of positive electrode material, preferably a strip-like main region provided with a layer of positive electrode material;
- a free edge strip not provided with electrode material, extending along a first edge of the cathode current collector, in particular along a first longitudinal edge of the cathode current collector; have
f. The electrode-separator assembly is in the form of a roll having two end faces or is part of a stack formed from two or more identical electrode-separator assemblies, also having two end faces. have.
g. The electrode-separator assembly is enclosed in a housing, optionally with other identical electrode-separator assemblies or multiple other identical electrode-separator assemblies of a stack.
h. The anode and cathode are arranged such that the first edge or longitudinal edge of the anode current collector protrudes from one of the end faces or sides of the stack and the first edge or longitudinal edge of the cathode current collector is in the stack. formed and/or positioned relative to each other within the electrode-separator assembly so as to protrude from the other of the end faces or sides of the electrodes.
i. The cell has contact plate metal members, preferably longitudinally, in direct contact with one of the first edges or the longitudinal edges.
j. The contact plate metal member is connected to this edge or longitudinal edge by welding.

The cell includes two contact plate metal members, one in direct contact with the first edge or longitudinal edge of the anode current collector and the other in direct contact with the first edge of the cathode current collector. and the contact plate metal members and the edges or longitudinal edges in contact with those members, respectively, are joined together by welding. preferable.

The current collector has the function of electrically contacting the electrochemically active constituents contained in the electrode material over as large an area as possible. It is preferred that the current collector is made of metal or at least surface metallized. Suitable metals for the anode current collector include copper or nickel, or other conductive materials, especially alloys of copper and nickel or metals coated with nickel. Stainless steel is also generally possible. Suitable metals for the cathode current collector include aluminum or other conductive materials, especially aluminum alloys.

The anode current collector and/or the cathode current collector are each preferably a metal foil with a thickness in the range of 4 μm to 30 μm, especially a ribbon-like metal foil with a thickness in the range of 4 μm to 30 μm.

However, in addition to foils, other ribbon-like substrates such as metal or metal-coated nonwovens or open-pore foams can be used as current collectors.

The current collector is preferably equipped on both sides with the respective electrode material.
In free edge strips, the respective current collector metals are free of the respective electrode material. The metal of each current collector is preferably uncoated in these regions so that electrical contact can be made, for example by welding.

However, in some embodiments, the metal of each current collector in the free edge strip is coated with a support material that is more heat resistant than the current collectors coated with this support material. sometimes

"More refractory" in this context is intended to mean that the support material remains solid at temperatures at which the metal of the current collector melts. Therefore, the support material has a higher melting point than the metal, or the support material sublimates or decomposes only at temperatures at which the metal is already molten.

Both the anode current collector and the cathode current collector each have a free edge strip along a first edge, preferably a first longitudinal edge, which free edge strip is provided with the respective electrode material. preferably not. In a further development, both at least one free edge strip of the anode current collector and at least one free edge strip of the cathode current collector are preferably coated with a support material. It is particularly preferred that the same support material is used for each of those regions.

Support materials that can be used within the scope of the present invention can in principle be metals or metal alloys, which or have a higher melting point than the metals constituting the surface coated with the support material. provided that However, in many embodiments it is preferred that the lithium-ion cell according to the invention has at least one of the further features a to d indicated immediately below:
a. The support material is a non-metallic material.
b. The support material is an electrically insulating material.
c. Non-metallic materials are ceramic materials, glass-ceramic materials, or glasses.
d. The ceramic material may be aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium aluminum nitride (TiAlN), silicon oxide, especially silicon dioxide (SiO ₂ ) or titanium carbonitride (TiCN). is.

It is particularly preferred according to the invention that the support material is formed according to the preceding characteristic b, particularly preferably according to the preceding characteristic d.

The term non-metallic material includes in particular plastic, glass and ceramic materials.
The term "electrically insulating material" should be understood broadly in this context. In principle, an electrically insulating material includes any electrically insulating material, in particular a material also referred to as plastic.
The term ceramic material should be understood broadly in this context. In particular, ceramic materials include carbides, nitrides, oxides, silicides, or mixtures and derivatives of these compounds.
The term "glass-ceramic material" specifically means a material comprising crystalline grains entrapped in an amorphous glassy phase.
The term "glass" basically refers to any inorganic glass that meets the thermal stability criteria defined above and is chemically stable to any electrolyte that may be contained in the cell. means.

It is particularly preferred that the anode current collector consists of copper or a copper alloy while the cathode current collector consists of aluminum or an aluminum alloy and the support material is aluminum oxide or titanium oxide.

It may be further preferred that the free edge strips of the anode current collector and/or the cathode current collector are coated with a strip of support material.

The main regions, in particular the strip-like main regions of the anode and cathode current collectors, preferably extend parallel to the respective edges or longitudinal edges of the current collectors. The strip-shaped main regions preferably extend over at least 90%, particularly preferably at least 95%, of the area of the anode and cathode current collectors.

In some preferred embodiments, the support material is preferably applied adjacent to the strip-shaped main area, but does not completely cover the free area. For example, the support material may be along the edges of the anode and/or cathode current collectors, particularly along the length of the anode and/or cathode current collectors, so as to only partially cover each edge strip. It is applied in the form of strips or lines along the directional edges. An elongated partial area of the free edge strip may remain uncovered directly along this edge or longitudinal edge.
It is particularly preferred that the lithium ion cell according to the invention is a secondary lithium ion cell.

Basically all known electrode materials for secondary lithium ion cells can be used for the anode and cathode of the cell.

Carbon-based particles, such as graphitic carbon or non-graphitic carbon materials capable of intercalating lithium, preferably also in the form of particles, can be used as the active material for the negative electrode. Alternatively or additionally, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) or a derivative thereof may be included in the negative electrode, preferably in the form of particles.

However, in a highly preferred embodiment, the cell according to the invention has, in addition to the essential features a to j mentioned above, a feature k shown immediately below:
k. The negative electrode material is selected as active material from the group consisting of silicon, aluminum, tin, antimony, and compounds or alloys of these materials that are capable of reversibly intercalating and deintercalating lithium. at least one material in an amount of 20 wt% to 90 wt%.
The weights given herein refer to the dry weight of the negative electrode material, ie the weight without the electrolyte and without taking into account the weight of the anode current collector.

As mentioned earlier, tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. The ability to absorb lithium, especially for silicon, exceeds that of graphite or similar materials by many times.

Among the active materials mentioned above, which are preferably used in the form of particles, silicon is particularly preferred. Cells in which the negative electrode contains between 20 wt % and 90 wt % of silicon as active material are particularly preferred according to the invention.

Some compounds of silicon, aluminum, tin, and/or antimony are also capable of reversibly depositing and extracting lithium. For example, in some preferred embodiments, silicon may be included in the negative electrode in the form of an oxide. In these embodiments, it may be preferred that the negative electrode comprises silicon oxide in an amount ranging from 20 wt% to 90 wt%.

The design of the cell according to the invention allows great advantages. As mentioned earlier, electrodes whose current collectors are electrically connected through the first-mentioned separate conductive tabs should be in the immediate vicinity of the conductive tabs rather than further away from the conductive tabs. , experience greater thermomechanical stress during charging and discharging. This difference is particularly pronounced for negative electrodes containing silicon, aluminum, tin, and/or antimony as active materials.

The electrical connection of the current collectors through the contact plate metal members not only allows for relatively uniform and efficient heat dissipation within cells according to the invention, but also reduces the thermomechanical effects that occur during charging and discharging. Stress is evenly distributed across the winding. Surprisingly, this makes it possible to control a very high proportion of silicon and/or tin and/or antimony in the negative electrode. At rates above 50%, damage resulting from thermomechanical loading occurs relatively infrequently or not at all during charging and discharging. For example, increasing the proportion of silicon in the anode can significantly increase the energy density of the cell.

Those skilled in the art will appreciate that tin, aluminum, silicon, and antimony are not necessarily metals in their purest form. For example, the silicon particles may contain traces or some other elements, in particular other metals (in each case except lithium, which is contained depending on the state of charge), e.g. It may also be included, in particular in proportions of up to 10% by weight. Therefore, alloys of tin, aluminum, silicon and antimony can also be used.

In a particularly preferred embodiment, the cell according to the invention has at least one of the features a and b indicated immediately below:
a. The negative electrode material further comprises, as negative active material, carbon-based particles capable of reversible lithium uptake and release, such as graphitic carbon, especially mixtures of silicon and these carbon-based particles.
b. Carbon-based particles capable of intercalating lithium are included in the electrode material in a proportion of 5 wt % to 75 wt %, in particular in a proportion of 15 wt % to 45 wt %.

In a further particularly preferred embodiment, the cell according to the invention has at least one of the following features ac indicated immediately below:
a. The negative electrode material contains an electrode binder and/or a conductive agent.
b. The electrode binder is contained in the negative electrode material in a proportion of 1 wt % to 15 wt %, especially in a proportion of 1 wt % to 5 wt %.
c. The conductive agent is contained in the negative electrode material in a proportion of 0.1 wt % to 15 wt %, particularly in a proportion of 1 wt % to 5 wt %.

The immediately preceding features ac are particularly preferably realized in combination with one another.

The active material is preferably incorporated in the matrix of the electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other.

The conductive agent has a function of increasing the conductivity of the electrode. Common electrode binders are based, for example, on polyvinylidene fluoride (PVDF), polyacrylic acid, or carboxymethylcellulose. Common conductive agents are carbon black and metal powders.

In the context of the present invention it is particularly preferred that the positive electrode material comprises a PVDF binder and the negative electrode material comprises a polyacrylate binder, especially lithium polyacrylate.

Suitable active materials for the positive electrode include lithium metal oxide compounds and lithium metal phosphate compounds such as _LiCoO2 and _LiFePO4 . In addition, _lithium nickel manganese cobalt oxide (NMC) with the formula _{LiNixMnyCozO2} (where x+y+z _is usually 1) is particularly well suited, and lithium manganese spinel ( _{LMO )} with the formula _LiMn2O4 ), or lithium _{nickel cobalt} alumina ( _NCA ) whose chemical formula is _{LiNixCoyAlzO2} , where x+y+z are usually 1. Derivatives _thereof such _as lithium nickel manganese _cobalt alumina ( _NMCA ) _or Li _{1 +x M−} O compounds and/or mixtures of the aforementioned materials can also be used.

The high silicon content in the anode of cells according to the invention requires a correspondingly high capacity cathode to achieve good cell balance. Therefore, NMC, NCA or NMCA are particularly preferred.

In a particularly preferred embodiment, the cell according to the invention has at least one of the features a to e indicated immediately below:
a. The positive electrode material comprises as active material at least one metal oxide compound capable of reversible lithium uptake and release, preferably one of the compounds mentioned above, in particular NMC, NCA or NMCA.
b. The at least one oxide compound is present in the electrode material in a proportion of 50% to 99% by weight, in particular in a proportion of 80% to 99% by weight.
c. Preferably, the positive electrode material also contains an electrode binder and/or a conductive agent.
d. The electrode binder is contained in the positive electrode material in a proportion of 1 wt % to 15 wt %, in particular in a proportion of 2 wt % to 5 wt %.
e. The conductive agent is contained in the positive electrode material at a ratio of 0.1 wt% to 15 wt%.

The immediately preceding features a to e are particularly preferably realized in combination with one another.

In the case of both positive and negative electrodes, it is preferred that the percentages of each component contained in the electrode material add up to 100% by weight.

High capacity cathodes can reversibly store lithium in the range of 200-250 mAh/g, while silicon has a theoretical capacity of about 3500 mAh/g. This results in a relatively thick cathode with high surface charge and a very thin anode with low surface charge. Materials such as silicon react strongly to small voltage changes due to their very high capacitance, so the anode current collector should be coated as uniformly as possible. Small differences in current collector loading and/or electrode material compaction can lead to large local deviations in electrode balance and/or stability.

For this reason, in a preferred embodiment the cell according to the invention has the characteristics indicated immediately below:
a. The weight per unit area of the negative electrode (120) deviates from the average value by at most 2% per unit area of at least 10 cm ² .

The average value is the quotient of the sum of the results of at least 10 measurements divided by the number of measurements performed.

Furthermore, the cell preferably comprises at least one lithium salt-based electrolyte such as, for example, lithium hexafluorophosphate (LiPF ₆ ) dissolved in an organic solvent (eg, a mixture of organic carbonates).

In a particularly preferred embodiment, the cell according to the invention has at least one of the features a to d indicated immediately below:
a. The cell contains an electrolyte comprising a mixture of tetrahydrofuran (THF) and 2-methyltetrahydrofuran (mTHF).
b. The volume ratio of THF:mTHF in the mixture is in the range from 2:1 to 1:2, preferably 1:1.
c. The cell contains an electrolyte containing LiPF ₆ as a conducting salt.
d. 1.5-2.5M, in particular 2M, conductive salt contained in the electrolyte.

It is particularly preferred that the electrolyte of the cell according to the invention is characterized by all of the features a to d above.

In an alternative and particularly preferred embodiment, the cell according to the invention has at least one of the features a to e indicated immediately below:
a. The cell contains an electrolyte comprising a mixture of fluoroethylene carbonate (FEC) and ethylmethyl carbonate (EMC).
b. The volume ratio of FEC:EMC in the mixture is in the range from 1:7 to 5:7, preferably 3:7.
c. The cell contains an electrolyte containing LiPF ₆ as a conducting salt.
d. The conducting salt is contained in the electrolyte at a concentration of 1.0-2.0M, especially 1.5M.
e. The electrolyte contains vinylene carbonate (VC), in particular in a proportion of 1 to 3% by weight.

It is particularly preferred that the electrolyte of the cell according to the invention is characterized by all of the features a to e above.

A separator is, for example, an electrically insulating plastic membrane that can be permeated by an electrolyte because it has micropores. The foil may be formed from polyolefin or polyetherketone, for example. Nonwovens and wovens made from such plastic materials can also be used as separators.

To improve cycling stability, the cathode-to-anode capacitance ratio of a cell according to the invention is balanced so that the potential capacitance of silicon is not fully utilized. preferably.

It is particularly preferred that the cell according to the invention has the characteristic a indicated immediately below:
e. The cathode-to-anode capacitance of the cell of the present invention is balanced so that only 700-1500 mAh per gram of negative electrode material is reversibly used during operation.
This measure can significantly reduce the volume change.

The ribbon-shaped anode and the ribbon-shaped cathode are offset from each other within the electrode-separator assembly such that a first longitudinal edge of the anode current collector protrudes from one of the end faces and the cathode collector. It is preferably ensured that the first longitudinal edge of the electrical body protrudes from the other of the end faces.

In fabricating the electrode and separator assembly, care is usually taken to ensure that their current collectors of opposite polarity do not protrude from one side, as this can lead to short circuits. This is because it may increase the risk of However, the staggered placement of the anodes and cathodes described above minimizes the risk of short circuits, because those current collectors of opposite polarity are connected to opposite end faces of the windings or stacks. because it protrudes from the opposite side.

Those current collector protrusions resulting from the staggered arrangement may be utilized in accordance with the present invention, preferably over their entire length, by contacting them by a suitable shunt regulator. According to the present invention, the contact plate metal member described above acts as a diverter. Such electrical contact greatly reduces the internal resistance within the cell according to the invention. Therefore, the configuration described above can very well absorb the occurrence of large currents. Minimizing internal resistance reduces heat loss at high currents. Furthermore, it is advantageous for the dissipation of thermal energy from the wound electrode-separator assembly. Under heavy loads, heating is evenly distributed rather than localized.

In addition to the elements mentioned above, the lithium-ion cell according to the invention expediently also comprises a housing consisting of two or more housing parts, which in an airtight and/or liquidtight manner takes the form of a roll. It is preferred to enclose the assembled electrode-separator assembly.

When contact plate metal members are used, it is generally necessary to electrically connect the contact plate metal members to the housing or to electrical conductors led out of the housing. For example, the contact plate metal member may be connected to the housing part directly or via electrical conductors.

When the electrode-separator assembly is part of a stack of two or more identical electrode-separator assemblies, those identical electrode-separator assemblies are located at the edge of the anode current collector, optionally at the anode current collector. The longitudinal edges and the cathode current collector edges, optionally also the cathode current collector longitudinal edges, are arranged in the stack such that each project from the same page of the stack. Therefore, all anode current collectors and all cathode current collectors can be in electrical contact simultaneously with the same contact plate metal member at any one time.

In a particularly preferred embodiment, the cell according to the invention is characterized in that part of the housing serves as the contact plate metal member and/or the contact plate metal member forms part of the housing enclosing the electrode-separator assembly. and

These embodiments are particularly advantageous. On the one hand, it is optimal in terms of heat dissipation. The heat generated inside the winding can be dissipated directly into the housing via the edges, especially the longitudinal edges. Secondly, the internal volume of the housing with given external dimensions can be utilized almost optimally in this way. Each separate contact plate metal member and each separate electrical conductor for connecting the contact plate metal member to the housing requires space inside the housing and increases the weight of the cell. By eliminating such separate components, this space becomes available for active material. Therefore, the energy density of the cell according to the invention can be further increased.

In a first, particularly preferred contact variant, the cell according to the invention has at least one of the features a and b indicated immediately below, particularly preferably a combination of the two features:
a. The housing comprises a cup-shaped first housing part having a bottom and peripheral side walls and an opening, and a second housing part closing the opening.
b. The contact plate metal member is the bottom of the first housing part.

The housing is preferably cylindrical or prismatic in shape. Thus, the cup-shaped first housing part preferably has a circular or rectangular cross-section, and the second housing part and the bottom of the first housing part are preferably circular or rectangular in shape.

If the electrode-separator assembly is in the form of a roll with two end faces, the housing is preferably cylindrical. On the other hand, if the electrode-separator assembly is part of a stack of two or more identical electrode-separator assemblies, the housing is preferably prismatic.

When the housing is cylindrical, the housing generally includes a cylindrical housing shell and a circular upper part and a circular lower part, whereby in this variant the first housing part consists of the housing shell and the circular and the second housing part corresponds to the circular upper part. A circular top part and/or a circular bottom part may serve as contact plate metal members.

If the housing is prismatic, it generally comprises several rectangular side walls, as well as a polygonal, in particular rectangular, upper part and a polygonal, in particular rectangular lower part, whereby this deformation In an example, the first housing part includes side walls and a polygonal bottom part, and the second housing part corresponds to a circular polygonal top part. The upper part and/or the lower part may serve as contact plate metal members.

Both the first and the second housing part preferably consist of an electrically conductive material, in particular a metallic material. These housing parts can, for example, independently of each other consist of nickel-plated steel sheets or alloyed or unalloyed aluminum.

In a preferred further development of the first contact variant, the cell according to the invention has at least one of the features a to e indicated immediately below, in particular a combination of features a to e:
a. The cell has a contact plate metal member, and a first edge or longitudinal edge of the anode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The rim is joined by welding with this contact plate metal member.
b. The cell has a contact plate metal member, and the first edge or longitudinal edge of the cathode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The edges are connected with this contact plate metal member by welding.
c. One of the contact plate metal members is the bottom of the first housing part.
d. The other of the contact plate metal members is connected to the second housing part via electrical conductors.
e. The cell includes a seal that electrically isolates the first and second housing parts from each other.

In this embodiment, conventional housing components can be used to enclose the electrode-separator assembly. No space is wasted for conductors placed between the bottom and the electrode-separator assembly. No separate contact plate metal member is required on the bottom side. An electrically insulating seal can be attached to one edge of the second housing part to close the housing. The assembly consisting of the second housing part and the seal can be inserted into the opening of the first housing part and mechanically fixed there, for example by crimping.

In a particularly preferred embodiment of the first contact variant, the second housing part may also serve as contact plate metal member. In this embodiment, the cell according to the invention has at least one of the immediately following characteristics, in particular the combination of the following immediately following characteristics a to e:
a. The cell has a contact plate metal member, and a first edge or longitudinal edge of the anode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The rim is joined by welding with this contact plate metal member.
b. The cell has a contact plate metal member, and the first edge or longitudinal edge of the cathode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The edges are connected with this contact plate metal member by welding.
c. One of the contact plate metal members is the bottom of the first housing part.
d. The other of the contact plate metal members is the second housing component.
e. The cell includes an electrical seal that electrically isolates the first and second housing parts from each other.

In this embodiment, no electrical conductors are required on either page of the electrode-separator assembly to connect the contact plate metal members to the housing parts. On one page, one of the contact plate metal members also serves as a housing part, and on the other page, part of the housing serves as the contact plate metal member. The space inside the housing can be optimally used.

In a further preferred further development of the first contact variant, the cell according to the invention has at least one of the features a to e indicated immediately below:
a. The cell has a contact plate metal member, and a first edge or longitudinal edge of the anode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The rim is joined by welding with this contact plate metal member.
b. The cell has a contact plate metal member, and the first edge or longitudinal edge of the cathode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The edges are connected with this contact plate metal member by welding.
c. One of the contact plate metal members is the bottom of the first housing part.
d. A second housing part is welded to the opening of the first housing part and includes a pole stud surrounded by a pole bushing, eg an electrical insulator, through which the conductor leads out of the housing.
e. The other of the contact plate metal members is electrically connected to this conductor.

The immediately preceding features a to e are particularly preferably realized in combination with one another.

In this embodiment, those housing parts are welded together and thus electrically connected. For this reason, the aforementioned pole bushing is required.

In a second preferred contact variant, the cell according to the invention has at least one of the features a and b indicated immediately below, particularly preferably a combination of the two features:
a. The housing comprises a tubular first housing part having two end openings, a second housing part closing one of the openings and a third housing part closing the other of the openings. .
b. The contact plate metal member is the second housing part or the third housing part.

Also in this contact variant, the housing of the cell is preferably cylindrical or prismatic. Preferably, the tubular first housing part has a circular or rectangular cross-section and the second and third housing parts are circular or rectangular.

When the housing is cylindrical, the first housing part is generally hollow cylindrical and the second and third housing parts are circular and serve as the contact plate metal member and as the bottom and lid. , which can close the first housing part at the ends.

Where the housing is prismatic, the first housing part generally comprises a plurality of rectangular side walls joined together by common edges, and the second and third housing parts are each polygonal, particularly rectangular. is. Both the second and third housing parts may serve as contact plate metal members.

Both the first and the second housing part preferably consist of an electrically conductive material, in particular a metallic material. For example, the housing parts may consist of nickel-plated steel, stainless steel (eg of type 1.4303 or 1.4304), copper, nickel-plated copper, or alloyed or non-alloyed aluminum. . It may also be preferred that the housing part electrically connected to the cathode consists of aluminum or an aluminum alloy and the housing part electrically connected to the anode consists of copper or a copper alloy or nickel-plated copper.

The main advantage of this variant is that it eliminates the need for a cup-shaped housing part to be produced by upstream molding and/or casting operations to form the housing. Instead, the tubular first housing part serves as the starting point.

In a preferred further development of the second variant, the cell according to the invention has at least one of the features a to e indicated immediately below, in particular a combination of features a to e indicated immediately below:
a. The cell has a contact plate metal member, and a first edge or longitudinal edge of the anode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The rim is joined by welding with this contact plate metal member.
b. The cell has a contact plate metal member, and the first edge or longitudinal edge of the cathode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The edges are connected with this contact plate metal member by welding.
c. One of the contact plate metal members is welded to one of the end openings of the first housing part and is the second housing part.
d. A third housing part is welded to the other of the end openings of the first housing part and comprises a pole stud surrounded by a pole bushing, e.g. an electrical insulator, through which the conductor leads out of the housing. .
e. The other of the contact plate metal members is electrically connected to this conductor.

The immediately preceding features a to e are particularly preferably realized in combination with one another.

In an even more preferred further development of the second variant, the cell according to the invention has at least one of the features a to d indicated immediately below:
a. The cell has a contact plate metal member, and a first edge or longitudinal edge of the anode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The rim is joined by welding with this contact plate metal member.
b. The cell has a contact plate metal member, and the first edge or longitudinal edge of the cathode current collector is in direct contact with the contact plate metal member, preferably longitudinally, and the edge or longitudinal edge is in direct contact with the contact plate metal member. The edges are connected with this contact plate metal member by welding.
c. One of the contact plate metal members is welded to one of the end openings of the first housing part and is the second housing part.
d. The other of the contact plate metal members closes the other of the end openings of the first housing part as a third housing part and is insulated from the first housing part by a seal.

Features a to d indicated immediately above are particularly preferably realized in combination with each other.

Both embodiments are characterized in that, on one side of the housing, the contact plate metal member serves as housing part and is connected to the first housing part by welding. On the other side, the contact plate metal member can also serve as a housing part. However, it must be electrically insulated from the first housing part. Alternatively, pole bushings could be used here.

The pole bushing of the cell according to the invention includes an electrical insulator that prevents electrical contact between the housing and electrical conductors leading out of the housing. The electrical insulator can be, for example, a glass or ceramic material or plastic.

The electrode-separator assembly is preferably in the form of a cylindrical roll. Providing the electrodes in such a wound form allows a particularly advantageous use of the space within the cylindrical housing. Therefore, the housing is also cylindrical in the preferred embodiment.

In another preferred embodiment, the electrode-separator assembly is in the form of a prismatic winding. Providing the electrodes in such a wound form allows a particularly advantageous use of the space within the prismatic housing. Therefore, in the preferred embodiment the housing is also prismatic.

Additionally, a prismatic housing may be very well filled by a prismatic stack of the same electrode-separator assemblies introduced above. For this purpose it may be particularly preferred that the electrode-separator assembly has a substantially rectangular basic shape.

All of the above embodiments, especially the first and second, in which part of the housing serves as the contact plate metal member and/or the contact plate metal member forms part of the housing enclosing the electrode-separator assembly. It should be emphasized that the contact variant may also be implemented completely independently from feature k of claim 1. The invention therefore also includes a cell having features a to j of claim 1, in which part of the housing serves as the contact plate metal member and/or the contact plate metal member forms part of the housing. Although formed, the anode does not necessarily contain silicon, aluminum, tin, and/or antimony as active material in proportions of 20% to 90% by weight.

In a particularly preferred embodiment, the cell according to the invention is characterized by at least one of the features ac indicated immediately below:
a. The strip-shaped main region of the current collector connected to the contact plate metal member by welding, preferably the strip-shaped main region of the current collector connected to the contact plate metal member by welding, has a plurality of apertures.
b. The apertures of the main area are round or square holes, especially punched or drilled holes.
c. The current collector, which is connected to the contact plate metal member by welding, is perforated in the main region, in particular by round or slotted perforations.

Multiple apertures result in reduced volume and reduced weight of the current collector. This makes it possible to introduce more active material into the cell and thus dramatically increase the energy density of the cell. In this way the energy density can be increased up to a double digit percentage range.

In some preferred embodiments, the apertures are introduced into the strip-like main regions by a laser.

In principle, the aperture geometry is not critical to the invention. Importantly, as a result of inserting the apertures, the volume of the current collector is reduced and the apertures can be filled with active material, thus providing more space for active material.

On the other hand, when inserting an aperture, it can be very advantageous to ensure that the maximum diameter of the aperture is not too large. Preferably, the aperture should not exceed twice the thickness of the layer of electrode material on each current collector.

In a particularly preferred embodiment, the cell according to the invention is characterized by feature a indicated immediately below:
a. The diameter of the apertures in the current collector, especially in the main area, is in the range of 1 μm to 3000 μm.

Within this preferred range, diameters in the range from 10 μm to 2000 μm, preferably from 10 μm to 1000 μm, especially from 50 μm to 250 μm are more preferred.

It is particularly preferred that the cell according to the invention has at least one of the features a and b indicated immediately below:
a. A contact plate metal member joined to a current collector by welding has a lower weight per unit area than a free edge strip of the same current collector, at least in a portion of the main area.
b. A current collector connected to a contact plate metal member by welding has fewer or no apertures per unit area in the free edge strip than in the main area.

The immediately preceding features a and b are particularly preferably realized in combination with each other.

Anode current collector and cathode current collector free edge strips bound the main region to a first edge or first longitudinal edge. Both the anode and cathode current collectors preferably comprise free edge strips along both edges, particularly along both longitudinal edges.

Apertures characterize the main area. In other words, the boundary between the main area and the free edge strip corresponds to the transition between the apertured and non-apertured areas.
Preferably, the apertures are substantially evenly distributed over the main area.

In a further particularly preferred embodiment, the cell according to the invention has at least one of the characteristics ac indicated immediately below:
a. The weight per unit area of the current collector in the main region is reduced by 5% to 80% compared to the weight per unit area of the current collector in the free edge strip.
b. The hole area of the current collector is in the range of 5% to 80% in the main area.
c. The current collector has a tensile strength of 20 N/mm ² to 250 N/mm ² in the main area.

Hole area, often referred to as free cross-sectional area, may be determined according to ISO 7806-1983. The tensile strength of the current collector in the main region is reduced compared to a current collector without apertures. The determination can be made according to DIN EN ISO 527 Part 3.

The anode current collector and cathode current collector are preferably identical or similar in terms of apertures. Each achievable energy density improvement is added together. Therefore, in preferred embodiments, the cell according to the invention has at least one of the features ac indicated immediately below:
a. Both the anode current collector main area and the cathode current collector main area, preferably the strip-like anode current collector main area and the strip-like cathode current collector main area, are characterized by a plurality of apertures.
b. The cell includes a contact plate metal member resting on one of the first edge or the longitudinal edge as the first contact plate metal member, and further includes a contact plate metal member on one of the first edge or the longitudinal edge. A second contact plate metal member resting on the other.
c. A second contact plate metal member is connected to this other edge or longitudinal edge by welding.

The immediately preceding features ac are particularly preferably realized in combination with one another. However, features b and c may also be implemented in combination without feature a.

The preferred embodiment of the apertured current collector described above is independently applicable to the anode and cathode current collectors.

The use of perforated current collectors or otherwise multi-apertured current collectors has not yet been seriously explored in lithium-ion cells because such current collectors can be used in electrical applications. This is because it is very difficult to bring them into direct contact with each other. As mentioned earlier, electrical connections to current collectors are often made through separate conductive tabs. However, reliable welding of these conductor tabs to perforated current collectors in an industrial mass production process is difficult to achieve without an acceptable error rate.

According to the invention, this problem is solved by welding the edge of the current collector to the contact plate metal member, as described above. The concept according to the invention makes it possible to completely dispense with separate conductor tabs, thus allowing the use of current collectors with low material content and apertures. Especially in embodiments in which the free edge strips of the current collector are not apertured, welding can be performed reliably with very low rejection rates.

When a very thin metal foil is used as the current collector, the edges of the current collector, especially the longitudinal edges of the current collector, can be very mechanically sensitive and can interfere with contact plate metal members. Unintentionally large depressions or melting may occur during welding. Furthermore, melting of the separator of the electrode-separator assembly can occur during welding of the contact plate metal members. The support layer described above works to counteract this effect.

All the embodiments described above, in which the preferably strip-shaped main region of the current collector connected to the contact plate metal member by welding has a plurality of apertures, are realized completely independently of feature k of claim 1 It should be emphasized that The invention therefore also includes a cell having the features a to j of claim 1, in which the strip-like main region of the current collector connected to the contact plate metal member by welding has a plurality of apertures. , the anode does not necessarily contain 20% to 90% by weight of silicon, aluminum, tin and/or antimony as active material.

The concept of welding the edge of the current collector with the contact plate metal member is already known from WO 2017/215900 A1 or JP 2004-119330. The use of the contact plate metal member makes it possible to particularly increase the current-carrying capacity and reduce the internal resistance. Therefore, with regard to the method of electrically connecting the contact plate metal member to the edge of the current collector, full reference is made to the contents of WO2017/215900A1 and JP2004-119330A.
Preferred contact plate metal members for use in the present invention are sometimes referred to as contact plates. In a preferred embodiment, the contact plate metal member is plate-shaped.

In some preferred embodiments, the cell according to the invention has at least one of the features a and b indicated immediately below:
a. As contact plate metal elements, in particular as contact plates, metal plates are used having a thickness in the range from 50 μm to 600 μm, preferably from 150 to 350 μm.
b. The contact plate metal member, in particular the contact plate, consists of alloyed or unalloyed aluminium, titanium, nickel or copper, optionally stainless steel (e.g. of type 1.4303 or 1.4304) or It also consists of nickel-plated steel.

The thicknesses indicated above are preferred both when the contact plate metal member is part of the housing and when the contact plate metal member does not serve as part of the housing.

In particular, in embodiments in which the contact plate metal member, particularly the contact plate, does not serve as part of the housing, the contact plate metal member may have at least one slot and/or at least one perforation. They have the function of counteracting the effects of deformation of sheet metal parts, especially plates, during the production of welded joints.

Especially in embodiments where the contact plate metal member, especially the contact plate, serves as part of the housing, slots and perforations are preferably omitted. However, such contact plate metal members, particularly such contact plates, may have apertures, particularly holes in the central region.

If the housing is cylindrical, preferably a contact plate metal member, especially a contact plate, in the shape of a disc, in particular a circular or at least approximately circular disc, is used. They then have disc edges that are circular or at least approximately circular on the outside. In this context, a generally circular disc is to be understood in particular as a disc in the shape of a circle with at least one cut-off circular segment, preferably two to four cut-off circular segments.
If the housing is cylindrical, preferably a contact plate metal member, in particular a contact plate, of rectangular basic shape is used.

In a particularly preferred embodiment, both the anode current collector and the contact plate welded thereto, in particular the contact plate welded thereto, consist of the same material. It is particularly preferred that this material is selected from the group comprising copper, nickel, titanium, nickel plated steel and stainless steel.
In a further particularly preferred embodiment, both the cathode current collector and the contact plate welded thereto, in particular the contact plate welded thereto, consist of the same material. It is particularly preferred that this material is selected from the group comprising alloyed or unalloyed aluminium, titanium and stainless steel (eg of type 1.4404).

As mentioned above, the cell according to the invention has a contact plate metal member, one of the first edges, in particular one of the first longitudinal edges, preferably longitudinally extending its contacts. Direct contact with sheet metal members. This may result in linear contact zones.

In a preferred realizable development, the cell according to the invention has at least one of the features ac indicated immediately below:
a. A first edge of the anode current collector, in particular a first longitudinal edge of the anode current collector, is preferably in direct longitudinal contact with the contact plate metal member and is welded to the contact plate metal member. , where a linear contact zone exists between the edge or longitudinal edge and the contact plate metal member.
b. A first edge of the cathode current collector, in particular a first longitudinal edge of the cathode current collector, is preferably in direct longitudinal contact with the contact plate metal member and welded to the contact plate metal member. , where a linear contact zone exists between the edge or longitudinal edge and the contact plate metal member.
c. A first edge or longitudinal edge of the anode current collector and/or a first edge or longitudinal edge of the cathode current collector includes one or more sections, each of which is separated by a welded seam. , is continuously connected to the respective contact plate metal member along its entire length.

The immediately preceding features a and b can both be implemented independently of each other or in combination. However, features a and b are preferably implemented in both cases in combination with feature c shown immediately above.

The contact plate metal member allows electrical contact to be made over the entire length of the current collector and thus also the associated electrode. This greatly reduces the internal resistance in the cell according to the invention. Therefore, the configuration described above can absorb the generation of large currents well. Minimizing internal resistance reduces heat loss at high currents. Furthermore, it is advantageous for the dissipation of thermal energy from the electrode-separator assembly.

There are several ways in which the contact plate metal members can be connected to the edges, especially the longitudinal edges.

The contact plate metal members may be joined to the edges or longitudinal edges along linear contact zones by at least one welded seam. The edge or longitudinal edge thus comprises one or more sections, each of which is continuously connected over its entire length to the contact plate metal member or contact plate metal members by a welded seam. be. It is particularly preferred that the sections have a minimum length of 5 mm, preferably 10 mm and particularly preferably 20 mm.

In one possible further development, the section or sections which are continuously connected to the contact plate metal member over their entire length are at least 25% of the total length of the respective edge or longitudinal edge, It preferably extends over at least 50%, particularly preferably over at least 75%.
In some preferred embodiments, the edge or longitudinal edge is continuously welded to the contact plate metal member along its entire length.
In a further possible embodiment, the contact plate metal members are connected to respective edges or longitudinal edges via a plurality of welding spots.

When the electrode-separator assembly is in the form of a spiral winding, the longitudinal edges of the anode and cathode current collectors projecting from the end faces of the winding are also generally spiral. has a geometric shape. The same then applies to linear contact zones along which contact plate metal members are welded to their respective longitudinal edges.

When the electrode-separator assembly is part of a stack of two or more identical electrode-separator assemblies, the edges of the anode and cathode current collectors projecting from the end pages of the stack are of straight geometry. It often has a shape. The same then applies to linear contact zones along which contact plate metal members are welded to respective edges.

In a preferred further development which is also feasible, the cell according to the invention has at least one of the features ac indicated immediately below:
a. The separator is a ribbon-shaped plastic substrate having a thickness in the range of 5 μm to 50 μm, preferably in the range of 7 μm to 12 μm, and having first and second longitudinal edges and two ends. Preferably.
b. The edges of the separator, particularly the longitudinal edges of the separator, form the terminal sides or end faces of the electrode-separator assembly.
c. The longitudinal edges or margins of the anode current collector and/or cathode current collector protruding from the end face of the winding or the side of the stack do not exceed 5000 μm, preferably 3500 μm.
The immediately preceding features ac are particularly preferably realized in combination with one another.

It is particularly preferred that the edge or longitudinal edge of the anode current collector protrudes from the end face of the page or roll of the stack by no more than 2500 μm, particularly preferably no more than 1500 μm. It is particularly preferred that the edges or longitudinal edges of the cathode current collector protrude from the end faces of the pages or rolls of the stack by no more than 3500 μm, particularly preferably no more than 2500 μm.

The anode current collector and/or cathode current collector protrusion numbers refer to the free protrusion before the page or edge is brought into contact with the contact plate metal member. Welding one or more contact plate metal members can cause deformations in the edges of the current collector.

If a smaller amount of free projection is chosen, a wider, preferably strip-shaped, main area of the current collector covered with the electrode material can be formed. This can make a positive contribution to the energy density of the cell according to the invention.

A lithium ion cell according to the invention may be a button cell. A button cell is cylindrical in shape with a height less than a diameter. The height is preferably in the range of 4mm to 15mm. More preferably, the button cell has a diameter in the range of 5 mm to 25 mm. Button cells are suitable, for example, for supplying electrical energy to small electronic devices such as watches, hearing aids, and wireless headphones.

Lithium-ion cells in the form of button cells according to the invention generally have a nominal capacity of up to 1500 mAh. The nominal capacity is preferably in the range of 100mAh to 1000mAh, particularly preferably in the range of 100 to 800mAh.

It is particularly preferred that the lithium-ion cell according to the invention is a cylindrical round cell. Cylindrical round cells are greater in height than in diameter. Cylindrical round cells are particularly suitable for applications in the automotive field, e-bikes or other applications with high energy requirements.

The height of lithium-ion cells designed as round cells is preferably in the range of 15 mm to 150 mm. The diameter of the cylindrical round cells is preferably in the range 10 mm to 60 mm. Within these ranges, for example, a form factor of 18×65 (diameter*height in mm) or 21×70 (diameter*height in mm) is particularly preferred. Cylindrical round cells with these form factors are particularly suitable for powering electric drives in automobiles.

The nominal capacity of the lithium-ion cell according to the invention, designed as a cylindrical round cell, is preferably up to 90000mAh. For the 21×70 form factor, the cell in one embodiment as a lithium-ion cell has a nominal capacity preferably in the range 1500 mAh to 7000 mAh, particularly preferably in the range 3000 to 5500 mAh. For the 18×65 form factor, the cell in one embodiment as a lithium-ion cell has a nominal capacity, preferably in the range 1000 mAh to 5000 mAh, particularly preferably in the range 2000 to 4000 mAh.

In the European Union, there are strict regulations on manufacturers providing information on the nominal capacity of secondary batteries. For example, information on the nominal capacity of secondary nickel-cadmium batteries shall be based on measurements according to the IEC/EN61951-1 and IEC/EN60622 standards and shall be based on secondary nickel-metal hydride batteries. batteries) shall be based on measurements according to the IEC/EN61951-2 standard, information on the nominal capacity of secondary lithium batteries shall be based on measurements according to the IEC/EN61960 standard. Information on the nominal capacity of secondary lead-acid batteries must be based on measurements according to the IEC/EN61056-1 standard. Information regarding nominal capacities in this application is also preferably based on these standards.

The anode current collector, cathode current collector, and separator are preferably ribbon-like in embodiments in which the cell according to the invention is a cylindrical round cell, and preferably have the following dimensions:
- Length in the range from 0.5 m to 25 m - Width in the range from 30 mm to 145 mm In these cases, the free edge strip extending along the first longitudinal edge not equipped with electrode material is 5000 μm. It is preferable to have the following widths.
For a cylindrical round cell with a form factor of 18×65, the current collector is
It preferably has a width of -56 mm to 62 mm, preferably 60 mm - a length of 1.5 m or less.
For a cylindrical round cell with a form factor of 21×70, the current collector is
It preferably has a width of -56 mm to 68 mm, preferably 65 mm - a length of 2.5 m or less.

Lithium ion cell function is based on the availability of sufficient mobile lithium ions (mobile lithium) to balance the current drawn by migration between the anode and cathode or between the negative and positive electrodes. there is Mobile lithium in the context of the present application means that lithium is available for storage and extraction processes at the electrode during the charging and discharging process of a lithium ion cell or is activated for this purpose. It should be understood that it represents the ability to During the charging and discharging process of lithium-ion cells, loss of mobile lithium occurs over time. These losses generally result from a variety of unavoidable side reactions. A loss of mobile lithium already occurs during the first charge-discharge cycle of a lithium-ion cell. During this first charge-discharge cycle, a top layer typically forms on the surface of the electrochemically active components on the negative electrode. This top layer is called the solid electrolyte interphase interface (SEI) and generally consists primarily of electrolyte decomposition products and a certain amount of lithium that is tightly bound in this layer.

The loss of mobile lithium associated with this process is particularly severe in cells where the anode has a silicon portion. To compensate for these losses, the cell according to the invention in preferred embodiments has at least one of the features a and b indicated immediately below:
a. The cell includes a reservoir of lithium or lithium-containing material not included in the positive and/or negative electrodes that can be used to compensate for the loss of mobile lithium within the cell during operation.
b. This reservoir is in contact with the electrolyte of the cell.
c. The cell has an electrical conductor and optionally also a controllable switch through which the reservoir can be electrically connected to the positive or negative pole.
The immediately preceding features ac are particularly preferably realized in combination with one another.

It is particularly preferred that the reservoir is arranged in the housing of the cell according to the invention and the electrical conductors are led from the housing, for example via suitable pole bushings, to electrical contacts that can be brought out from the outside of the housing. .

An electrically contactable lithium reservoir allows lithium to be supplied to the cell's electrodes as needed, or excess lithium to be released from the electrodes to prevent lithium plating. For this purpose, the lithium reservoir can be connected via an electrical conductor to the negative or positive electrode of the lithium ion cell. Excess lithium may be supplied to a lithium reservoir and stored there as needed. For these applications, separate monitoring of the anode and cathode potentials within the cell and/or external monitoring of cell balance via electrochemical analysis such as DVA (differential voltage analysis) is recommended. Means to enable may be provided.

The conductors and associated lithium reservoirs must be electrically isolated from the positive and negative electrodes and from the cell components to which they are electrically coupled.

The lithium or lithium-containing material of the lithium reservoir can be, for example, lithium metal, lithium metal oxide, lithium metal phosphate, or other materials well known to those skilled in the art.

Further features of the invention and advantages derived from it are shown in the drawings and the following description of the drawings. The embodiments described below are merely to illustrate and provide a better understanding of the invention and should not be taken as limiting in any way.

In the drawing the following are shown schematically.
FIG. 4A is a top view of a current collector in an embodiment according to the present invention; FIG. 2 is a cross-sectional view of the current collector shown in FIG. 1; FIG. 4A is a top view of an anode that can be processed into an electrode-separator assembly in the form of a roll. Figure 4 is a cross-sectional view of the anode shown in Figure 3; 4 is a top view of an electrode-separator assembly manufactured using the anode shown in FIG. 3; FIG. Figure 6 is a cross-sectional view of the electrode-separator assembly shown in Figure 5; 1 is a cross-sectional view of one embodiment of a cell according to the invention in the form of a cylindrical round cell; FIG. FIG. 4 is a cross-sectional view of a further embodiment of a cell according to the invention in the form of a cylindrical round cell; FIG. 4 is a cross-sectional view of a further embodiment of a cell according to the invention in the form of a cylindrical round cell; FIG. 4 is a cross-sectional view of a further embodiment of a cell according to the invention in the form of a cylindrical round cell; It had the form of a cylindrical round cell. Fig. 4 is a cross-sectional view of a further embodiment of a cell according to the invention;

1 and 2 show current collector 110 designs that can be used in cells according to the present invention. FIG. 2 is a cross-sectional view along _S1 . Current collector 110 includes a plurality of apertures 111 that are rectangular holes. Region 110a features an aperture 111, while no aperture is found in region 110b along longitudinal edge 110e. Thus, current collector 110 has a significantly lower weight per unit area in region 110a than in region 110b.

FIGS. 3 and 4 show an anode 120 made by applying negative electrode material 123 to both sides of current collector 110 shown in FIGS. FIG. 5 is a cross-sectional view along _S2 . Here, the current collector 110 comprises a strip-like main region 122 provided with a layer of negative electrode material 123 and a free edge strip 121 extending along the longitudinal edge 110e not provided with electrode material 123. have. In addition, electrode material 123 also fills aperture 111 .

FIGS. 5 and 6 show an electrode-separator assembly 104 made using the anode 120 shown in FIGS. Further, it includes cathode 115 and separators 118 and 119 . FIG. 6 is a cross-sectional view along _S3 . Cathode 115 is based on the same current collector design as anode 120 . The current collectors 110 and 115 of the anode 120 and cathode 130 preferably differ only in their respective material selections. For example, the current collector 115 of the cathode 130 has a strip-like main region 116 equipped with a layer of positive electrode material 125 and a free edge strip 117 extending along a longitudinal edge 115 e not equipped with electrode material 125 . , provided. Coiling may transform the electrode-separator assembly 104 into a coil such as may be contained within the cell of the present invention.
In some preferred embodiments, free edge strips 117 and 121 are coated on both sides and at least in some areas with one of the support materials described above.

FIG. 7 shows a cell 100 with a housing comprising first housing part 101 and second housing part 102 . Enclosed within the housing is an electrode-separator assembly 104 . The housing is generally cylindrical in shape, with housing component 101 having a circular bottom 101a, a hollow cylindrical shell 101b, and a circular opening opposite bottom 101a. Housing part 102 serves to close the circular opening and is formed as a circular lid. Electrode-separator assembly 104 is in the form of a cylindrical roll having two end faces.

For a prismatic housing, the cross section through the cell looks exactly the same. In this case, housing part 101 has a rectangular bottom 101a, rectangular side walls 101b and a rectangular cross-section, and a rectangular opening, and housing part 102 serves as a rectangular lid for closing the rectangular opening. It is formed. And reference number 104 in this case does not denote a cylindrical electrode-separator assembly, but rather a stack or prismatic roll of a plurality of identical electrode-separator assemblies.

Free edge strip 121 of anode current collector 110 protrudes from one end face of electrode-separator assembly 104 and free edge strip 117 of cathode current collector 115 protrudes from the other end face. The edge 110e of the anode current collector 110 is in direct contact with the bottom portion 101a of the housing part 101 over its entire length and is connected to the bottom portion 101a over at least some portions, preferably over its entire length, by welding. be. The edge 115e of the cathode current collector 115 is in direct contact with the plate-shaped contact plate metal member 105 over its entire length, and over at least some portions, preferably over its entire length, is welded to the contact plate. It is connected to the metal member 105 .

Contact plate metal member 105 is then electrically connected to housing component 102 via electrical conductor 107 .
There are preferably welded connections between the conductors 107 and the contact plate metal member 105 on one page and between the conductors 107 and the housing part 102 on the other page, respectively.

Other than current collectors 110 and 115, other components of electrode-separator assembly 104 (particularly separators and electrode materials) are not shown for improved overview.
Housing parts 101 and 102 are electrically isolated from each other by seal 103 . The housing is closed, for example by a flange attachment process. Housing part 101 forms the negative electrode and housing part 102 forms the positive electrode of cell 100 .

FIG. 8 shows a cell 100 with a housing comprising first housing part 101 and second housing part 102 . Enclosed within the housing is an electrode-separator assembly 104 . The housing is generally cylindrical in shape, with housing component 101 having a circular bottom 101a, a hollow cylindrical shell 101b, and a circular opening opposite bottom 101a. Housing part 102 serves to close the circular opening and is formed as a circular lid. Electrode-separator assembly 104 is in the form of a cylindrical roll having two end faces.

For a prismatic housing, the cross section through the cell looks exactly the same. In this case, housing part 101 has a rectangular bottom 101a, rectangular side walls 101b and a rectangular cross-section, and a rectangular opening, and housing part 102 serves as a rectangular lid for closing the rectangular opening. It is formed. And reference number 104 in this case does not denote a cylindrical electrode-separator assembly, but rather a stack or prismatic roll of a plurality of identical electrode-separator assemblies.

Free edge strip 121 of anode current collector 110 protrudes from one end face of electrode-separator assembly 104 and free edge strip 117 of cathode current collector 115 protrudes from the other end face. The edge 110e of the anode current collector 110 is in direct contact with the bottom portion 101a of the housing part 101 over its entire length and is connected to the bottom portion 101a over at least some portions, preferably over its entire length, by welding. be. The edge 115e of the cathode current collector 115 is in direct contact with the contact plate metal member 105 over its entire length and is welded to the contact plate metal member 105 over at least some portions, preferably over its entire length. connected to

The contact plate metal member 105 is directly connected to the metal pole stud 108, preferably welded. It is led out of the housing through an aperture in housing part 102 and is insulated from housing part 102 by electrical insulator 106 . Pole stud 108 and electrical insulator 106 together form a pole bushing.

Other than current collectors 110 and 115, other components of electrode-separator assembly 104 (particularly separators and electrode materials) are not shown here for improved overview.

The bottom part 101a has a hole 109, which can be used, for example, to introduce an electrolyte into the housing and is closed, for example by soldering, welding or gluing. Alternatively, holes can be provided in the housing part 102 for the same purpose.

Housing part 102 is welded to the circular opening of housing part 101 . Housing parts 101 and 102 therefore have the same polarity and form the negative electrode of cell 100 . Pole stud 108 forms the positive electrode of cell 100 .

FIG. 9 shows a cell 100 with a housing comprising first housing part 101 and second housing part 102 . Enclosed within the housing is an electrode-separator assembly 104 . The housing is generally cylindrical in shape, with housing component 101 having a circular bottom 101a, a hollow cylindrical shell 101b, and a circular opening opposite bottom 101a. Housing part 102 serves to close the circular opening and is formed as a circular lid. Electrode-separator assembly 104 is in the form of a cylindrical roll having two end faces.

For a prismatic housing, the cross section through the cell looks exactly the same. In this case, housing part 101 has a rectangular bottom 101a, rectangular side walls 101b and a rectangular cross-section, and a rectangular opening, and housing part 102 serves as a rectangular lid for closing the rectangular opening. It is formed. And reference number 104 in this case does not denote a cylindrical electrode-separator assembly, but rather a stack or prismatic roll of a plurality of identical electrode-separator assemblies.

Free edge strip 121 of anode current collector 110 protrudes from one end face of electrode-separator assembly 104 and free edge strip 117 of cathode current collector 115 protrudes from the other end face. The edge 110e of the anode current collector 110 is in direct contact with the bottom portion 101a of the housing part 101 over its entire length and is connected to the bottom portion 101a over at least some portions, preferably over its entire length, by welding. be. The edge 115e of the cathode current collector 115 is in direct contact with the housing part 102 over its entire length and is connected to the housing part 102 by welding over at least some portions, preferably over its entire length. .

Other than current collectors 110 and 115, other components of electrode-separator assembly 104 (particularly separators and electrode materials) are not shown here for improved overview.

A hole 109, closed for example by soldering, welding or gluing, is found in the bottom part 101a, which hole can serve for example for introducing an electrolyte into the housing. Another hole 109 can be found in housing part 102 which can serve the same purpose. This hole is preferably closed by a pressure relief valve 141 which can be welded to the housing part 102, for example.

Both of these holes 109 shown are generally not required. Therefore, in many cases the cell 100 shown in FIG. 9 has only one of the two holes.

Housing parts 101 and 102 are electrically isolated from each other by seal 103 . The housing is closed, for example by a flange attachment process. Housing part 101 forms the negative electrode and housing part 102 forms the positive electrode of cell 100 .

FIG. 10 shows a cell 100 with a housing including first housing part 101 and second housing part 102 and third housing part 155 . The electrode-separator assembly 104 is enclosed within a housing. The housing has a generally cylindrical shape, the housing part 101 here being formed as a hollow cylinder with two circular end face openings. Housing parts 102 and 155 serve to close the circular opening and are formed as circular lids. Electrode-separator assembly 104 is in the form of a cylindrical roll having two end faces.

For a prismatic housing, the cross section through the cell looks exactly the same. In this case housing part 101 has a rectangular cross-section and two rectangular openings, and housing parts 102 and 155 are rectangular lids for closing the rectangular openings. And reference number 104 in this case does not denote an electrode-separator assembly in cylindrical form, but a stack or prismatic roll of several identical electrode-separator assemblies.

Free edge strip 121 of anode current collector 110 protrudes from one end face of electrode-separator assembly 104 and free edge strip 117 of cathode current collector 115 protrudes from the other end face. Edge 110e of anode current collector 110 is in direct contact with housing part 155 over its entire length and is connected to housing part 155 by welding over at least some portions, preferably over its entire length. . The housing part 155 therefore also functions as a contact plate metal member or contact plate within the meaning of the invention. The edge 115e of the cathode current collector 115 is in direct contact with the contact plate metal member 105 over its entire length and is welded to the contact plate metal member 105 over at least some portions, preferably over its entire length. connected to

Other than current collectors 110 and 115, other components of electrode-separator assembly 104 (particularly separators and electrode materials) are not shown here for improved overview.

The contact plate metal member 105 is directly connected to the metal pole stud 108, preferably welded. It is led out of the housing through an aperture in housing part 102 and is insulated from housing part 102 by electrical insulator 106 . Pole stud 108 and electrical insulator 106 together form a pole bushing.

The housing part 102 has a hole 109 which can be used, for example, to introduce an electrolyte into the housing and which is closed, for example by soldering, welding or gluing. Alternatively, holes can be provided in the housing part 155 for the same purpose.

Housing parts 102 and 155 are welded to the circular opening of housing part 101 . Accordingly, housing parts 101 , 102 and 155 have the same polarity and form the negative electrode of cell 100 . Pole stud 108 forms the positive electrode of cell 100 .

FIG. 11 shows a cell 100 with a housing comprising first housing part 101 and second housing part 102 . Enclosed within the housing is an electrode-separator assembly 104 . The housing is generally cylindrical in shape, with housing component 101 having a circular bottom 101a, a hollow cylindrical shell 101b, and a circular opening opposite bottom 101a. Housing part 102 serves to close the circular opening and is formed as a circular lid. Electrode-separator assembly 104 is in the form of a cylindrical roll having two end faces.

For a prismatic housing, the cross section through the cell looks exactly the same. In this case, housing part 101 has a rectangular bottom 101a, rectangular side walls 101b and a rectangular cross-section, and a rectangular opening, and housing part 102 serves as a rectangular lid for closing the rectangular opening. It is formed. And reference number 104 in this case does not denote a cylindrical electrode-separator assembly, but rather a stack or prismatic roll of a plurality of identical electrode-separator assemblies.

Free edge strip 121 of anode current collector 110 protrudes from one end face of electrode-separator assembly 104 and free edge strip 117 of cathode current collector 115 protrudes from the other end face. The edge 110e of the anode current collector 110 is in direct contact with the bottom portion 101a of the housing part 101 over its entire length and is connected to the bottom portion 101a over at least some portions, preferably over its entire length, by welding. be.

The edge 115e of the cathode current collector 115 is in direct contact with the housing part 102 over its entire length and is connected to the housing part 102 by welding over at least some portions, preferably over its entire length. . Thus, here the housing part 102 simultaneously serves as a contact plate metal member or contact plate.

Anode current collector 110 is equipped with a layer of negative electrode material 123 on each side, but has a free edge strip 121 extending along a longitudinal edge 110 e that is not equipped with electrode material 123 . Instead, the free edge strip 121 is coated on both sides with a ceramic support material 165 .

Cathode current collector 115 is equipped with a layer of negative electrode material 125 on each side, but has a free edge strip 117 extending along a longitudinal edge 115 e that is not equipped with electrode material 125 . Instead, the free edge strip 117 is coated on both sides with a ceramic support material 165 .

Electrode-separator assembly 104 has two end faces formed by longitudinal edges 118a and 119a and 118b and 119b of separators 118 and 119. As shown in FIG. The longitudinal edges of current collectors 110 and 115 protrude from these end faces. The corresponding protrusions are labeled d1 and d2.

A hole 109 is found in the housing part 102, which can be used, for example, to introduce an electrolyte into the housing. This hole is closed, for example, by a pressure relief valve 141 connected to the housing part 102 by welding.

Housing parts 101 and 102 are electrically isolated from each other by seal 103 . The housing is closed by a flange attachment process. For this purpose, the opening edge 101c of the housing part is bent radially inwards. Housing part 101 forms the negative electrode and housing part 102 forms the positive electrode of cell 100 .

The cell shown in FIG. 11 can be manufactured according to FIG. 12, the individual processing steps AI being described below. First, an electrode-separator assembly 104 is provided, on the upper end face of which is arranged a housing part 102 which serves as a contact plate metal member or contact plate. This is welded in step B to the longitudinal edge 115e of the cathode current collector 115 . In step C, a perimeter seal 103 is applied to the edges of housing component 102 . Along with this, at step D, the electrode-separator assembly 104 is inserted into the housing part 101 until the longitudinal edge 110e of the anode current collector 110 is in direct contact with the bottom 101a of the housing part 101 . In step E it is welded to the bottom 101a of the housing part 101 . In step F, the housing is closed by a flange attachment process. For this purpose, the opening edge 101c of the housing part 101 is bent radially inwards. In step G, the housing is filled with electrolyte, which is metered into the housing through opening 109 . The opening 109 is closed in steps H and I by a pressure relief valve 141 welded to the housing part 102 .

For example, the electrode-separator assembly 104 may include a positive electrode of 95 wt% NMCA, 2 wt% electrode binder, and 3 wt% carbon black as a conductive agent. A negative electrode may comprise a porous conductive matrix having an open pore structure.

For example, the electrode-separator assembly 104 has a positive electrode of 95 wt% NMCA, 2 wt% electrode binder, and 3 wt% carbon black as a conductive agent, 70 wt% silicon, 25 wt% graphite, 2 wt% electrode binder. , and 3 wt % carbon black as a conductive agent. A 2M solution of _LiPF6 in THF/mTHF (1:1) or a 1.5M solution of _LiPF6 in FEC/EMC (3:7) with 2 wt% VC can be used as electrolyte.

Claims (11)

A lithium-ion cell characterized by:
a. said cell comprising a ribbon electrode-separator assembly (104) having an anode (120)/separator (118)/cathode (130) sequence;
b. said anode (120) comprises a ribbon-like anode current collector (110) having a first longitudinal edge (110e) and a second longitudinal edge and two ends;
c. Said anode current collector (110) comprises a strip-like main region (122) equipped with a layer of negative electrode material (123) and said first longitudinal edge not equipped with said electrode material (123). a free edge strip (121) extending along (110e);
d. said cathode (130) comprises a ribbon-like cathode current collector (115) having a first longitudinal edge (115e) and a second longitudinal edge and two ends;
e. Said cathode current collector (115) comprises a strip-like main region (116) equipped with a layer of positive electrode material (125) and said first longitudinal edge not equipped with said electrode material (125). a free edge strip (117) extending along (115e);
f. Said electrode-separator assembly (104) is in the form of a roll with two end faces, or is formed by two or more identical electrode-separator assemblies (104) and has two end faces. be part of a stack that also has
g. said electrode-separator assembly (104) is enclosed in a housing, optionally with further identical electrode-separator assemblies of said stack;
h. The anode (120) and the cathode (130) are arranged such that the first longitudinal edge (110e) of the anode current collector (110) protrudes from one of the end faces or sides of the stack, and formed relative to each other within the electrode-separator assembly (104) such that the first longitudinal edges (115e) of the cathode current collectors (115) protrude from the other of the end faces or sides of the stack. being placed and/or arranged;
i. said cells having contact plate metal members (101a, 102, 155) in direct contact with one of said first longitudinal edges (110e, 115e);
j. said contact plate metal members (101a, 102, 155) are connected to said longitudinal edges (110e, 115e) by welding;
As well as additional distinguishing features:
k. Said negative electrode material (123), as an active material, is at least selected from the group consisting of silicon, aluminum, tin, antimony, and compounds or alloys of these materials capable of reversibly taking up and releasing lithium. containing one material in an amount of 20 wt% to 90 wt%;
Lithium ion cell with Additional features:
a. Said negative electrode material (123) further comprises, as a negative active material, carbon-based particles capable of reversible lithium uptake and release, such as graphitic carbon, especially mixtures of said silicon and these carbon-based particles. ,
b. said carbon-based particles capable of intercalating lithium are contained in said electrode material in a proportion of 5 wt% to 75 wt%, in particular in a proportion of 15 wt% to 45 wt%;
2. The cell of claim 1, comprising: Additional features:
a. the negative electrode material (123) comprises an electrode binder and/or a conductive agent;
b. The electrode binder is contained in the negative electrode material (123) at a rate of 1 wt% to 15 wt%;
c. The conductive agent is contained in the negative electrode material (123) at a rate of 0.1 wt% to 15 wt%;
3. The cell of claim 1 or claim 2, comprising at least one of: Additional features:
a. Said positive electrode material (125) comprises as active material at least one metal oxide compound capable of reversible deposition and extraction of lithium, preferably one of the compounds mentioned above, in particular NMC, NCA or NMCA matter,
b. at least one cobalt oxide and/or manganese compound is included in said electrode material (125) in an amount of 80 wt% to 99 wt%;
c. the cathode material (125) comprises an electrode binder and/or a conductive agent;
d. The electrode binder is contained in the positive electrode material (125) at a rate of 1 wt% to 15 wt%;
e. The conductive agent is contained in the positive electrode material (125) at a rate of 0.1 wt% to 15 wt%;
A cell according to any preceding claim, comprising at least one of Additional features:
a. the weight per unit area of said negative electrode (120) deviates from the mean by a maximum of 2% per unit area of at least 10 ^cm2 ;
A cell according to any preceding claim, comprising at least one of Additional features:
a. said cell comprising an electrolyte comprising a mixture of tetrahydrofuran (THF) and 2-methyltetrahydrofuran (mTHF);
b. the volume ratio of THF:mTHF in said mixture is in the range from 2:1 to 1:2, particularly preferably 1:1;
c. said cell comprising an electrolyte comprising LiPF ₆ as a conducting salt;
d. said conductive salt in a proportion of 1.5 to 2.5M, especially 2M, contained in said electrolyte;
A cell according to any preceding claim, comprising at least one of Additional features:
a. said cell comprising an electrolyte comprising a mixture of fluoroethylene carbonate (FEC) and ethyl methyl carbonate (EMC);
b. the volume ratio of FEC:EMC in said mixture is in the range from 1:7 to 5:7, particularly preferably 3:7;
c. said cell comprising an electrolyte comprising LiPF ₆ as a conducting salt;
d. the conductive salt is contained in the electrolyte at a concentration of 1.0 to 2.0M, especially 1.5M;
e. the electrolyte contains vinylene carbonate, in particular in a proportion of 1 to 3% by weight;
A cell according to any preceding claim, comprising at least one of Additional features:
a. said strip-like main regions (110a) of said current collectors (110, 115) connected to said contact plate metal members (101a, 102, 155) by welding having a plurality of apertures (111);
b. said apertures (111) in said main area (110a) are round or square holes, in particular punch or drill holes;
c. said current collector (110) connected to said contact plate metal member (101a, 102, 155) by welding is perforated in said main region (110a), in particular by perforation of round or slotted holes;
A cell according to any preceding claim, comprising at least one of Additional features:
a. said apertures (111) in said current collector (110), in particular in said main region (110a), having an average diameter in the range of 1 μm to 2000 μm;
A cell according to any one of claims 1 to 8, comprising Additional features:
a. Said current collector (110) joined to said contact plate metal member (101a, 102, 155) by welding is, at least in part of said main region (110a), said free edge strip of the same current collector (110). having a lower weight per unit area than (110b);
b. The current collector (110) connected to the contact plate metal members (101a, 102, 155) by welding has more apertures (111 ) is small or non-existent,
A cell according to any preceding claim, comprising at least one of Additional features:
a. The weight per unit area of the current collector (110) at the main region (110a) is 5 compared to the weight per unit area of the current collector (110) at the free edge strip (110b). % to 80%,
b. The hole area of the current collector (110) is within the range of 5% to 80% in the main region (110a);
c. The current collector (110) has a tensile strength of 20 N/mm ² to 250 N/mm ² in the main region (110a);
A cell according to any preceding claim, comprising at least one of

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